An unusual regulatory mechanism that controls the motile/non-motile option in genetically identical Salmonella also impacts the bacteria’s ability to cause infection.
As Salmonella divides into genetically identical clones, either of the two forms of the bacteria can emerge. Some individuals sport flagella — thin, whip-like projections that propel the bacterium. Others do not. When grown in a petri dish, both types appear.
Scientists at the University of Washington discovered that a protein that is almost in a class by itself –YdiV — determines whether a Salmonella cell will produce or not produce flagellin. This protein needed to make flagella, called flagellin, provokes the body’s defenses.
Not producing the flagellin means that the Salmonella does not provoke the hosts immune system. In an animal or human, anatomical location determines which type will fare better during each stage of the infection.
This gives the sub-populations an overall better chance of survival in the host.
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